blob: ac4bddf669de2195bce0864a28308031602245da [file] [log] [blame]
/* Instantiate a public key crypto key from an X.509 Certificate
* Copyright (C) 2012, 2016 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
#define pr_fmt(fmt) "ASYM: "fmt
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <crypto/public_key.h>
#include "asymmetric_keys.h"
static bool use_builtin_keys;
static struct asymmetric_key_id *ca_keyid;
#ifndef MODULE
static struct {
struct asymmetric_key_id id;
unsigned char data[10];
} cakey;
static int __init ca_keys_setup(char *str)
if (!str) /* default system keyring */
return 1;
if (strncmp(str, "id:", 3) == 0) {
struct asymmetric_key_id *p = &;
size_t hexlen = (strlen(str) - 3) / 2;
int ret;
if (hexlen == 0 || hexlen > sizeof( {
pr_err("Missing or invalid ca_keys id\n");
return 1;
ret = __asymmetric_key_hex_to_key_id(str + 3, p, hexlen);
if (ret < 0)
pr_err("Unparsable ca_keys id hex string\n");
ca_keyid = p; /* owner key 'id:xxxxxx' */
} else if (strcmp(str, "builtin") == 0) {
use_builtin_keys = true;
return 1;
__setup("ca_keys=", ca_keys_setup);
* restrict_link_by_signature - Restrict additions to a ring of public keys
* @trust_keyring: A ring of keys that can be used to vouch for the new cert.
* @type: The type of key being added.
* @payload: The payload of the new key.
* Check the new certificate against the ones in the trust keyring. If one of
* those is the signing key and validates the new certificate, then mark the
* new certificate as being trusted.
* Returns 0 if the new certificate was accepted, -ENOKEY if we couldn't find a
* matching parent certificate in the trusted list, -EKEYREJECTED if the
* signature check fails or the key is blacklisted and some other error if
* there is a matching certificate but the signature check cannot be performed.
int restrict_link_by_signature(struct key *trust_keyring,
const struct key_type *type,
const union key_payload *payload)
const struct public_key_signature *sig;
struct key *key;
int ret;
pr_devel("==>%s()\n", __func__);
if (!trust_keyring)
return -ENOKEY;
if (type != &key_type_asymmetric)
sig = payload->data[asym_auth];
if (!sig->auth_ids[0] && !sig->auth_ids[1])
return 0;
if (ca_keyid && !asymmetric_key_id_partial(sig->auth_ids[1], ca_keyid))
return -EPERM;
/* See if we have a key that signed this one. */
key = find_asymmetric_key(trust_keyring,
sig->auth_ids[0], sig->auth_ids[1],
if (IS_ERR(key))
return -ENOKEY;
if (use_builtin_keys && !test_bit(KEY_FLAG_BUILTIN, &key->flags))
ret = -ENOKEY;
ret = verify_signature(key, sig);
return ret;